Many have argued that the Confederate flag isn’t a symbol of racism so much as one of southern heritage. This is an impossible case to make, and the KKK’s support of the flag is only confirmation of its violent, racist past. In fact, the KKK’s association with the flag may be the reason it is flying in South Carolina today at all.

Decommissioned Confederate soldiers founded the Ku Klux Klan in Tennessee in the mid-1860s. The group was initially intended as a fraternal social organization, and early on, members were known to play tricks on freed slaves, like pretending to be dead Confederate soldiers raised from the dead. Their symbols at the time included white hoods and white sheets, which may have been connected to such pranks. But the group’s antics quickly escalated into violence and murder. By 1870, Congress passed several “Enforcement Acts” aimed at suppressing the KKK’s tactics of violence, intimidation, and interference, seeking to protect black Southerners who were registering to vote, voting, serving on juries, and holding political office. Many consider the Ku Klux Klan America’s “first true terrorist group.”

The KKK was significantly diminished for the next few decades, but saw a tremendous resurgence in 1915 due to the film The Birth of a Nation, which has been called “the first ever Hollywood blockbuster.” Released on the 50th anniversary of the end of the Civil War, the film was based on a popular novel called The Clansman, which celebrated the Klan and the way of life its members sought to defend. A scene in the movie inspired the group to adopt cross-burnings as a part of their tradition and symbolism going forward. According to Euan Hague, a professor at DePaul University, this was the height of the Klan’s popularity, in part because it came during an “anti-immigrant, anti-Catholic, anti-Jewish, and anti-Black” era. David Cunningham, a professor at Brandeis, agrees. “There were hundreds of thousands of members all over the country—Colorado, Oregon, Michigan, and well as in the South. They had a strong national presence, and influenced national politics.” By the 1930s, though, the group was in decline again.

There were some small local Klan resurgences through the ’50s, says Cunningham, “but then after the Civil Rights movement started … the resurgence in the 1950s and ’60s is really about resistance against the ‘imposition’ of northern and federal government on the southern way of life.” This is when the Confederate flag sees a major comeback. “The flag wasn’t absent,” says Cunningham, “but it had not been front and center as a political symbol. It was not shown or treated as a central symbol … Then the battle flag becomes this really direct symbol associated with the Civil War.” Cunningham dismisses the idea of the flag becoming popular again as primarily a symbol of Southern heritage. “It’s about defying challenges from outside of the white supremacist southern way of life, defiance, Jim Crow segregation.” Euan Hague agrees, “Advocates for the Confederate flag [say it was about] ‘100 years since the Civil War.’ It was as much if not more a sign of defiance against desegregation.”

According to both Cunningham and Hague, in the ’50s and ’60s the flag began to fly over statehouses and city halls in the south, and was embedded in state flags and other official state symbols. But the flag also began to appear in far more disturbing places: Klan rallies. At the time of the murder of civil rights activist Viola Liuzzo, who was killed just after the Selma to Montgomery march, there were Klan rallies of anywhere from 500 to 5,000 people happening somewhere in the South almost every single night, says David Cunningham. In a small town in North Carolina, the Klan celebrated three of Liuzzo’s murderers; there’s footage. Cunningham describes the rally as even “mainstream white southerners wildly cheering this murder… [And] very front and center is the waving of Confederate flags.” He continues. “It would be difficult to find any public presence of the Klan during that period that didn’t feature multiple Confederate flags.”

“There is a particular brand of southern life where the flag is used most pronouncedly,” says Cunningham. “We see the remobilization of the flag during the most pronounced defiance to civil rights... It gets brought out most strongly in times when white supremacy is attacked most directly.”

It shouldn’t surprise us, then, that a bitter battle over the Confederate flag has followed a year of scrutiny of police violence against unarmed black men, a fresh wave of civil rights activism and legislation, and the rise of #BlackLivesMatter and the movement it symbolizes. And it’s just as predictable that the KKK would rally around the Confederate flag on the South Carolina Statehouse grounds in the midst of a push to take it down. This isn’t about rallying for the Confederate flag, it's about rallying for what the flag represents for the Klan, which is what it represented for Charleston shooter Dylan Roof. In rallying around the flag, the Ku Klux Klan will be rallying around Roof, a man who murdered nine black Americans for being black. He committed exactly the kind of senseless, racist violence the group has always celebrated. The Confederate flag just happens to be one of their symbols.